Emergency Medicine

Question 1

Define shock.

Answer 1

Circulatory failure resulting in inadequate organ perfusion.

Often defined as systolic BP <90mmHg (or MAP <65mmHg) with evidence of tissue hypoperfusion.

Question 2

Name 5 signs of shock.

Answer 2

Mottled skin/pallor
Decreased GCS/agitation
Cool peripheries
Tachycardia
Increased CRT
Tachypnoea
Oliguria (<0.5ml/kg/hr)

Question 3

How would you class shock into 3 aetiological groups?

Answer 3

Hypovolaemic
Pump Failure
Distributive failure

Question 4

What are causes of hypovolaemic shock?

Answer 4

Blood loss - trauma, ruptured AAA or GI bleed

Fluid loss - burns, vomiting, diarrhoea or 3rd space losses (e.g. in pancreatitis or heat exhaustion)

Question 5

What are causes of shock due to pump failure?

Answer 5

Cardiogenic - ACS, arrhythmias, aortic dissection or acute valve failure

Secondary causes - PE, tension pneumothorax, cardiac tamponade

Question 6

What are causes of distributive shock?

Answer 6

Sepsis
Anaphylaxis
Neurogenic shock (SC injury, epidural or spinal anaethesia)
Endocrine (e.g. Addison’s disease or hypothyroidism)

Question 7

What causes shock in sepsis?

Answer 7

Any organism can cause vasodilatation, and therefore shock, due to release of inflammatory cytokines.
Gram -ve bacteria release endotoxins, which can cause sudden, severe shock without signs of infection.

Question 8

What is the most common cause of neurogenic shock?

Answer 8

Spinal cord transection, as this interrupts the autonomic nervous system below the level of injury.
It may result in decreased sympathetic tone and increased parasympathetic tone.